N excited hydrogen atom emits light with a wavelength of 397. 2 nm to reach the energy level for which n = 2. In which principal quantum level did the electron begin?.

b.false that your answer

answer;

18.5 seconds

explanation;

velocity is distance covered per unit time; it is given by displacement divided by time.

thus; time = displacement/velocity

total time = total displacement/velocity

total distance = 5000 meters south

total time = 5000/4.5

                  = 1111.11 seconds

but; 1 minute = 60 sec

thus; 1111.11 /60

                = 18.51 seconds

thus; the time taken is 18.5 seconds

the enthalpy change that occurs in a system when matter is transformed by a given chemical reaction, when all reactants and products are in their standard states.